Information regarding users of web sites (e.g. a consumer or potential consumer) is often a hidden and fragmented entity on the web. In some situations, an advertiser or web publisher may not have access to information for one or more web users' behavior on various sites on the web. Further, an advertiser may not be able to predict in real-time the audience of a proposed advertising campaign or determine audience correlations between two or more audiences (e.g. user populations). It is with respect to these considerations and others that the present invention is directed.